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Add-ons not working properly

  • 5 replies
  • 13 have this problem
  • 16737 views
  • Last reply by rmctoledo

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Recently (last 4-5 days my add-ons stopped working properly. Example: Tab Mix Plus shows as installed, but when any options I select do not affect tab behavior; Lastpass icon not showing up in the Add-on bar as it did previously; Newsfox icon doesn't appear in Toolbar as it did. Using Firefox 26.0 on Windows 8 on Dell Laptop.

Chosen solution

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the extensions.* files (e.g. extensions.sqlite, extensions.ini) and compatibibility.ini in the Firefox profile folder to reset the extensions registry.

New files will be created when required.

See "Corrupt extension files":

If you see disabled or not compatible extensions in "Firefox/Tools > Add-ons > Extensions" then click the Tools button at the left end of the Search Bar to check if there is a compatibibility update available.

If this hasn't helped then also delete the addons.sqlite file.


You can also check for problems caused by a corrupted localstore.rdf file.

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All Replies (5)

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Chosen Solution

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the extensions.* files (e.g. extensions.sqlite, extensions.ini) and compatibibility.ini in the Firefox profile folder to reset the extensions registry.

New files will be created when required.

See "Corrupt extension files":

If you see disabled or not compatible extensions in "Firefox/Tools > Add-ons > Extensions" then click the Tools button at the left end of the Search Bar to check if there is a compatibibility update available.

If this hasn't helped then also delete the addons.sqlite file.


You can also check for problems caused by a corrupted localstore.rdf file.

Modified by cor-el

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If i delete the extensions file, will I lose the data and settings associated with the specific add-on?

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No, such data is either stored in a separate file in the profile folder or as a pref in the prefs.js file (about:config shows such prefs).
Firefox will only rebuild the extension registry, so you might be getting a prompt to enable extensions.

You can still try to disable all extensions and check if enabling one of them has effect in case some are interfering.
This can also retrigger some actions that might help (i.e. rebuilding caches).

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I deleted the extensions* files in my profile and the also the addons.sqlite file. This seems to have solved my problem. Thank you for taking the time to address my problem.

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I've been having problems with my add-ons. Ad Block Plus will often hang Firefox and drive the CPU to 100%. I've reset Firefox and installed ABP, but still have the problem. My other extension have also stopped working. Any new extensions will appear to added on to Firefox, but they also don't work. I've followed all on-line trouble shooting options.